Eating quality of conventionally chilled sheep meat

Abstract

The meat and eating quality of the M. longissimus et lumborum (LL) from 80 adult sheep carcasses was examined. Half of the carcasses were subjected to the full range of electrical inputs that are routinely used at the abattoir: immobilisation, spinal discharge and high voltage stimulation (HVS), whereas the other half of the carcasses were subjected to all electrical inputs except HVS. HVS significantly decreased the first pH values and increased the average predicted temperature at pH 6.0. When the shear force of samples aged for 1 day was examined (n = 77), there was a significant effect of stimulation, such that non-stimulated meat was tougher. For a reduced sample (n = 40), the most influential effect on shear force was aging, with no significant effect of stimulation or interaction between stimulation and aging. This was such that aging reduced the percentage of samples with a shear force above 50 N from 75% after 1 day to 17.5% after 7 days of aging for the 40 LLs. When the LLs were aged for 7 days, there was no effect of stimulation on eating quality traits including tenderness, flavour, juiciness or overall liking. Based on the data for the LLs aged for 7 days, a relationship between overall liking and the overall ranking score was derived. Predicted overall liking scores at each rating score were derived, from which it was determined that to achieve a rating score of 3 (good every day), the overall liking score had to be 57. There was a significant interaction between category (less or greater than 57) and stimulation, such that for the less than 57 category, the mean overall liking score was lower for samples from non-stimulated carcasses (46.1) than those from stimulated carcasses (54.4). In the greater than 57 category, there was no difference between stimulated and non-stimulated samples with mean overall liking scores of 67.2 and 70.8, respectively. In total, 14% of samples had overall liking scores below 57. These results show that the proportion of very poor samples is reduced with stimulation even with aging and this is a very important outcome.